Extremely low thermal conductivity in BaSb2Se4: Synthesis, characterization, and DFT studies

• DOI: 10.1016/j.jssc.2022.123524
• Publication Date: 2022-08-31T07:17:43Z
• Authors: Subhendu Jana; Gopabandhu Panigrahi; Govind Ummethala; Arghya Ghosh; Sairam K. Malladi; Manish K. Niranjan; Jai Prakash

We report the synthesis of black-colored crystals and a polycrystalline phase of BaSb2Se4 by high-temperature reaction of elements at 1173 ?K and 973 ?K, respectively. The X-ray diffraction studies show that it crystallizes in the monoclinic P21/c space group, and the structure is composed of one-dimensional stripes of ?1[Sb2Se4]2? that are separated by the Ba2+ cations. The optical absorption study reveals the semiconducting nature (Eg ?= ?1.3(1) eV) of the polycrystalline BaSb2Se4 sample. A thermal conductivity (?) study shows a gradual decrease of the ?-value from ?0.39 ?W/mK to ?0.29 ?W/mK on heating the polycrystalline sample from 300 ?K to 773 ?K. The DFT study of the electronic structure of BaSb2Se4 shows that the bandgap is indirect with a magnitude in the range of ?1.0�1.6 ?eV depending on the choice of XC functional. The COHP analysis has been performed to investigate the relative strengths of chemical bonding between pertinent atoms in the BaSb2Se4 structure. � 2022 Elsevier Inc.